Atoms – Atoms are the building blocks of matter. An atom consists of a nucleus with positively charged protons and neutrally charged neutrons surrounded by negatively charged electrons. Different types of atoms have different numbers of protons in their nucleus. Think of an atom as a mini solar system with the protons and neutrons being the sun and electrons being the planets. The wires in your electrical system are made of matter, which is made of atoms.

Electrons – Because opposite charges attract, electrons are drawn to the protons in the nucleus, similar to how gravity keeps planets in orbit around the sun. Unlike planets, with their slow elliptical orbits that create centrifugal force to keep the planets from crashing into the sun, electrons repel each other due to their charge, and they orbit the nucleus at the speed of light in a path that is best described as a “probability cloud”.

Voltage, Volts, V, Potential, Charge – Because like charges repel, and electrons all have negative charges, this repulsion force builds up as a "pressure" when electrons are in close proximity to each other. This “pressure” in the context of an electrical system is known as Voltage.

Amperage, Amperes, Amps, A, Current, I - When electrons flow from a high voltage (pressure) area to a low voltage area, the flow rate is measured in Amps. An Amp is one coulomb per second. A coulomb is 6.241 x 10^18 (or 6,241,000,000,000,000,000) electrons.

Resistance, Ohms, Ω- Along the path from high voltage to low voltage areas, electrons encounter resistance. This resistance controls the flow rate like a nozzle on a hose. This resistance is measured in Ohms.

Watts, Energy, W – When flowing electrons encounter resistance, work can be performed. This is what makes electricity do things. This work can be measured in Watts and is equal to Volts times Amps (Watts = Volts x Amps).

When sunlight hits a solar panel, voltage and current are produced. This current, pushed by voltage, flows through wires in an electrical system to perform work when it encounters resistance, which can be measured in terms of watts.

To learn about Amp Hours, Watt hours and Power, go to the next section.